1. Field of the Invention
The present invention relates to a winged needle assembly and, more particularly, to a winged needle assembly having a winged cylindrical holder for preventing sticking accidents taking place when restoring the needle into a protector and which can protect the edge of the needle by merely sliding the needle along the inner wall of the winged cylindrical holder.
2. Description of the Prior Art
Conventionally, medical needles have usually been made separable from protectors in which they are accommodated. When used needles have been restored into the protectors, the fingers of operators often have been accidentally stuck by the edges (or tips) of the needles. As a result, there has been a possibility that medical personnel using such needles might be infected with AIDS or hepatitis. Therefore, in order to prevent such sticking accidents various proposals have been made. One of such proposals is a winged needle assembly disclosed in U.S. Pat. No. 5,120,320 wherein a protector having a pair of slits is integrally attached to the winged needle. In this assembly a used needle is allowed to slide backward along the slits of the protector to protect the edge of the used needle within the protector.
Another example is an injection needle assembly disclosed in Japanese Unexamined Patent Publication No. H-1-212561 wherein the injection needle assembly comprises an injection needle and a winged protector. In this assembly a required position regulating means is provided between the needle and the protector so that the edge of the needle can be protected within the protector by sliding the protector toward the distal end of the needle.
However, the winged needle assembly disclosed in above-mentioned U.S. Pat. No. 5,120,320 has the disadvantage that the needle can not be retracted into the protector while indwelling, since the wings fixed to the needle are secured to the skin of a patient by means of a tape or the like. Therefore, it is necessary for the needle to slide and be accommodated in the protector after removing the tape and drawing out the needle from the patient's skin.
The injection needle assembly disclosed in above-mentioned Japanese Unexamined Patent Publication No. H-1-212561 has the following problems due to its structural defects. When the needle is stuck into a patient's skin, the needle body moves backward due to the penetration force. The needle body tends to slip off the protector when it is pulled backward to retract the needle edge into the winged protector. Since the hub of the needle and the protector are to be firmly fitted with each other at a required position, the resistance in releasing the engagement of the two members after use or in sliding the hub along the inner wall of the protector is so large that the physical burden on medical personnel handling the needle assembly increases and the patient is given a sense of uneasiness.
In order to solve the above-described problems, the present applicant proposed in Japanese Unexamined Patent Publication No. H-7-5671 a winged needle assembly comprising a needle, a winged cylindrical holder for retaining the needle therein for protection and a hub which is movable from a first position at which the edge of the needle projects from the cylindrical holder by a predetermined length to a second position at which the edge of the needle is received within the cylindrical holder, and wherein interlocking means is provided between the hub and the cylindrical holder. In this assembly, at the first position at which the needle edge is exposed from the cylindrical holder by a predetermined length, the movement of the hub toward the second position at which the needle edge is received in the holder is prevented. While, after the hub has been slid to the second position, the movement of the hub toward the first position is prevented. However, this arrangement has not always satisfied medical personnel or patients using the winged needle assembly because when the interlocking means is released at the first position and the hub is moved toward the second position, there is some degree of frictional resistance.